diff ordinal.agda @ 142:c30bc9f5bd0d

Power Set
author Shinji KONO <kono@ie.u-ryukyu.ac.jp>
date Mon, 08 Jul 2019 12:13:19 +0900
parents 2a5519dcc167
children 3ba37037faf4
line wrap: on
line diff
--- a/ordinal.agda	Mon Jul 08 00:20:30 2019 +0900
+++ b/ordinal.agda	Mon Jul 08 12:13:19 2019 +0900
@@ -313,3 +313,12 @@
 TransFinite caseΦ caseOSuc record { lv = lx ; ord = (OSuc lx ox) } = 
       caseOSuc lx ox (TransFinite caseΦ caseOSuc  record { lv = lx ; ord = ox })
 
+--  (¬ (∀ y → ¬ ( ψ y ))) → (ψ y → p )  → p
+TransFiniteExists : {n : Level} → { ψ : Ordinal {n} → Set n } 
+  → (exists : ¬ (∀ y → ¬ ( ψ y ) ))
+  → {p : Set n} ( P : { y : Ordinal {n} } →  ψ y → p )
+  → p
+TransFiniteExists {n} {ψ} exists {p} P = ⊥-elim ( exists lemma ) where
+    lemma : (y : Ordinal {n} ) → ¬ ψ y
+    lemma y ψy = ( TransFinite {n} {{!!}} {!!} {!!} y ) ψy
+